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Project: PHASE ONE FIELD DEMONSTRATION OF  IN SITU GEOCHEMICAL STABILIZATION (ISGS) FOR CREOSOTE/PENTA  RESIDUALS (NAPL)

Site: KOPPERS INC., DENVER CO USA

EXECUTIVE SUMMARY

Beazer East, Inc. (Beazer) developed a Long-Term Interim Corrective Measures Compliance and Performance Monitoring Plan (GeoTrans, Inc.) for the various interim measures (IM) groundwater remedies at the Koppers Inc. Site in Denver, Colorado (KI Site). 

As described in the Corrective Measures Study Report (GeoTrans, Inc.), the IM ground water remedies were supplemented with the following technologies to enhance the removal of constituents of interest (COI) present in groundwater located off-property: 

i. Remediation by (monitored) natural attenuation (RNA);

ii. Phytoremediation; and

iii. In situ geochemical stabilization (ISGS) of creosote residuals.

This report describes the results of the initial (Phase I) engineering optimization field tests where 24,050 gallons of 3% aqueous permanganate (KMnO₄) solution was injected into 13 locations within a defined test area (75 x 95 ft).  Performance monitoring was conducted for 5 months to evaluate the ability ISBS using KMnO₄ to stabilize the suspected free-phase non-aqueous phase liquid (NAPL) residuals and enhance the natural attenuation processes by:

i. Mitigating the migration of NAPL;

ii. Reducing the concentration of COI in the dissolved-phase;

iii. Decreasing the mass of NAPL residuals (source reduction); and

iv. Reducing the flux of COI from NAPL residuals (especially true with MnO₂ precipitate).

As documented herein, the ISBS approach appeared to mitigate the migration of NAPL within the initial test area. As such, ISBS represents a useful tool for in situ NAPL management.  Information from the Phase I effort described herein has been used to modify the approach for possible continued, larger-scale implementation of the ISBS technology as a supplemental means of source area / NAPL management at the KI Denver Site.

REPORT CONCLUSIONS

Effective Radius of Influence: As applied to the KI Denver Site, permanganate application had an effective radius of influence of approximately 15 ft.

Changes in NAPL Thickness and Recovery:  There was a discernible decrease over time in the thickness of LNAPL for only those monitoring piezometers located within the permanganate treatment area. Changes in DNAPL thickness were not observed suggesting that vertical NAPL migration did not occur. In addition, there was a significant decrease in the amount of NAPL recovered within the ISBS treatment area.

Reduction in Soil Residuals:  ISBS yielded a 53% reduction in the residual mass of chlorinated phenols (from 285.4 to 133.8 mg/kg) and a 19% reduction in the mass of total PAHs (from 9,595 to 7,771 mg/kg). 

Decrease in Leachable Constituents:  Comparisons between the treated and background samples indicated a 76 % decrease in the total PAH leachable (from the treated soils.  The HMW PAHs present in the leachate was reduced more than 99% in the treated soils. 

Validation of Physicochemical Stabilization Processes Soil analytical data were consistent with those obtained from the complementary laboratory studies which showed preferential removal of LMW PAHs via oxidation/dissolution and stabilization of HMW residuals via physical encrustation/stabilization

Cumulatively, laboratory and field data validated the effectiveness of the ISBS process and its ability to reduce the flux of PAHs/penta into the dissolved phase.  Flux reduction should have a significant beneficial affect thereby accelerating the contraction of the dissolved phase COI plume at the KI Denver Site.

ORGANIZATIONS INVOLVED:

Beazer East, Inc. 

Prepared by:

Adventus Americas, Inc.

In association with:

GeoTrans, Inc.

The University of Waterloo